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IS 15525 (2004, Reaffirmed 2010) : Gaseous Fire 
Extinguishing Systems--IG 100 Extinguishing Systems. ICS 
13.220.10 




Jawaharlal Nehru 
'Step Out From the Old to the New" 



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Satyanarayan Gangaram Pitroda 
Invent a New India Using Knowledge 



Bhartrhari — Nitisatakam 
''Knowledge is such a treasure which cannot be stolen" 




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Indian Standard 

GASEOUS FIRE EXTINGUISHING SYSTEMS — 
IG 1 00 EXTINGUISHING SYSTEMS 



IS 15525 :2004 

REAFFIRJV'^ED 



ICS 13.220.10 



© BIS 2004 

BUREAU OF INDIAN STANDARDS 

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG 
NEW DELHI 110002 

September 2004 Price Group 5 



Fire Fighting Sectional Committee, CED 22 



FOREWORD 

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the Fire 
Fighting Sectional Committee had been approved by the Civil Engineering Division Council. 

The objective of this standard is to provide to the users of IG 100 systems with specific requirements for 
the control of fires of Class A and B type. It does not cover the design of explosion suppression systems. 

It is important that the fire protection of a building or plant be considered as a whole. IG 100 total flooding 
systems form only a part, though an important part, of the available fire protection facilities. It should not be 
assumed that the installation of an IG 100 total flooding system necessarily removes the need to consider 
supplementary measures, such as the provision of portable fire extinguishers or mobile appliances for flrst aid 
or emergency use, or measures to deal with special hazards. 

Controlled inert atmospheres are recognized as effective for extinguishing Class A and Class B fires where 
electrical risks are present. Nevertheless, it should not be forgotten, in the planning of comprehensive schemes, 
that there may be hazards for which this technique is not suitable, or that in certain circumstances or situations 
there may be danger in its use requiring special precautions. 



IS 15525 : 2004 



Indian Standard 

GASEOUS FIRE EXTINGUISHING SYSTEMS 
IG 100 EXTINGUISHING SYSTEMS 



1 SCOPE 

1.1 This standard sets out specific requirements 
for the design and installation of total flooding fire 
extinguishing systems employing IG 100 gas 
extinguishant. This standard is applicable to single 
supply as well as distributed supply systems. 

L2 This standard complements various general 
requirements applicable to all types of gaseous 
fire-extinguishing systems ( Halocarbon as well as 
Inert gas systems ) listed in IS 15493. As such, both 
these standards should be read together before 
designing a system. Where requirements in both 
the standards differ, this standard shall take 
precedence. 

1.3 This standard covers systems operating at 
nominal pressures of 1 5 MPa at 1 5°C and 20 MPa at 
l5°Conly. 

\A Before using IG 100, nature of fire and fire 
spread shall be studied for suitability of 
extinguishment as high discharge time of 60 s may 
not be suitable for rapid spreading fires. 

2 REFERENCES 

The standards given below contain provisions which 
through reference in this text, constitute provisions 
of this standard. At the time of publication, the editions 
indicated were valid. All standards are subject to 
revision, and the parties to agreements based on this 
standard are encouraged to investigate the possibility 
of applying the most recent editions of the standards 
indicated below: 



ISNo, 
7285:1988 



15493:2004 



Title 

Specification for seamless steel 
cylinders for permanent and high 
pressure liquefiable gases 
( second revision ) 



fire extinguishing 
General requirements 



Gaseous 

systems ■ 

3 GENERAL INFORMATION 

3.1 Application 

IG 100 total flooding system is designed to develop 
a controlled atmosphere in an enclosed space 
yielding a reduced oxygen concentration, which will 
not sustain combustion. The appropriate IG 100 



concentration shall also be maintained until the 
temperature within the enclosure has fallen below the 
reignition point. 

3.2 The minimum IG 100 concentration necessary to 
extinguish a flame and the minimum oxygen 
concentration necessary to support combustion 
have been determined by experiments for several 
surface-type fires particularly those involving liquids 
and gases. For deep-seated fires, longer soaking 
times may be necessary but are difficult to predict. 

3.3 It is important that residual oxygen 
concentrations are not only reached and maintained 
for a sufficient period of time to allow effective 
emergency action by trained personnel. This is 
equally important in all classes of fire since a 
persistent ignition source can lead to a recurrence of 
the initial event once the IG 100 has dissipated. 

4 GAS CHARACTERISTICS AND PROPERTIES 

4.1 IG 100 is a colourless, odourless and electrically 
non-conductive gas with a density approximately 
the same as that of air. 

4.2 IG 100 gas is nitrogen and its specification 
and physical properties are shown in Table 1 . 

4.3 IG 100 system can be used for extinguishing 
fires of all classes within the limits specified in 4 
of IS 15493. 

4.4 IG 100 gas shall comply with the specification 
as shown in Table 2. 

4.5 Toxicological information for IG 100 gas are 
shown in Table 3. 

4.6 Fill Pressure 

The fill pressure of the IG 100 cylinder shall not 
exceed the values provided in Table 4 for systems 
operating at 15 MPa and 20 MPa respectively. 

5 SAFETY OF PERSONNEL 

In addition to the provisions specified under 
IS 15493, the following requirements shall also apply. 

5.1 Protection of Occupants 

IG 100 total flooding systems shall not be used in 
design concentrations greater than 52 percent 
( corresponds to injected concentrations of 
74 percent ) in normally occupied areas, unless means 



IS 15525 : 2004 



Table 1 Physical Properties of IG 100 

( Clause 4.2 ) 



SI No. 


Property 


Value 


(1) 


(2) 


(3) 


i) 


Molecular mass 


28.02 


ii) 


Boiling point at 0.1 MPa, °C 


~ 195.8 


Hi) 


Freezing point, °C 


-210 


iv) 


Critical temperature, °C 


- 146.9 


V) 


Critical pressure, MPa 


3399 


vi) 


Specific volume of superheated 
vapour at 0.1 MPa and 20'^C 


0.858 



Table 2 Specification for IG 100 

{Clause A A) 

SI No. Specification Requirement 

(1) (2) (3) 

i) Purity 99.6 percent by volume, Min 

ii) Moisture 50 ( x ) 10"^ by mass, Max 

iii) Oxygen O.I percent by volume, Max 

NOTE — Other contaminants may include 
hydrocarbons, CO, NO, NO2, COj, etc. Most are less 
than 20 x 10"^ by mass, Max. 

Table 3 Toxicological Information for IG 100 

{Clause A.5) 

SI No. Property Value 

(1) (2) (3) 

i) No observed adverse effect level 43 percent 
(NOAEL) 

ii) Lowest observed adverse effect 52 percent 
level ( LOAEL ) 

NOTE — These values are the functional equivalents 
of NOAEL and LOAEL values which correspond to 
12 percent minimum oxygen for the no-effect level and 
10 percent minimum oxygen for the low-effect level. 

Table4 Fill Pressure of IG 100 Containers 

{Clause A. 6) 



SI No. 


System 


Property 


(1) 


(2) 


(3) 


i) 


15 MPa storage 
container 


Filling pressure at i5''C 


ii) 


15 MPa storage 


Maximum container working 




container 


pressure at 55°C 


iii) 


20 MPa storage 
container 


Filling pressure at I5°C 


iv) 


20 MPa storage 


Maximum container working 




container 


pressure at 55°C 



are provided to ensure safe egress of personnel prior 
to the discharge of the inert gas mixture. 

5.2 In areas, where there is a likelihood of significant 
difference between gross and net volumes of the 
enclosure, utmost care shall be exercised in proper 
system design. 

5.3 Though exposure to the concentration levels of 
oxygen and carbon dioxide ( 10 to 15 percent and 
4.5 to 5 percent by volume respectively ) is normally 
considered to produce a negligible risk to the 
personnel, contain provisions like personnel 
training, warning signs, pre-discharge alarms, and 
discharge inhibit switch shall be put in place. In 
addition, adequate ventilation facilities shall be 
available to exhaust the trapped gases following 
extinguishment process. 

5.4 Maximum safety precautions and safety 
limits that are associated with the use of IG 100 
are as shown in the Tables 5 and 6. Since a fire can 
be expected to consume oxygen and form 
decomposition products, personnel shall treat any fire 
situation as an emergency and promptly exit the 
enclosure. 

5.5 Additional provisions as shown in Table 7 
shall apply to account for failure of safeguards 
( see 5.1 to 5.4 ) to prevent accidental exposures 
to the humans present within the enclosure. 

6 ENCLOSURE STRENGTH AND VENTING 
FACILITIES 

6.1 Venting shall be provided at levels as high as 
possible in the enclosure. Strength and allowable 
pressures for average enclosures may be in 
conformity with the following guidelines. The 
building requirements for the type of enclosure 
and from venting required can also be calculated from 
the relevant specifications. 

6.2 Free venting facilities shall be provided for the 
enclosure and the equation for the venting area required 
shall be as follows: 



A^{5x\Q-^){QP~^'>) 



where 



NOTE — Figure \ {^ee page 7 ) should be referred for 
further data on pressure/temperature relationship. 



^ = free venting area, m^; 

g = lG-100 agent discharge rate, m^/ min; 
and 

P = allowable strength of the enclosure, 
kPa. 

Value of P for various construction types is 
shown in Table 8. ( For exceptionally tight 
enclosures, value of P shall be trebled. ) 



IS 15525 : 2004 



Table 5 Maximum Safety Precautions 

(Clause 5 A) 



SI No. 


IG 100 Design Concentration 
Percent by Volume 


Inhibit Switch 
and Time Delay 


Requirements 

Egress in Safety 
30 s, Max Interlock 




Lock-ofl 
Valve 


(1) 


(2) 


(3) 




(4) 


(5) 




(6) 


i) 


Below NOAEL< 43 


Required 




Not required 


Not required 




Not required 


ii) 


Between NOAEL and 
LOAEL 43 and 52 


Required 




Required 


Required 




Not required 


iii) 


Above LOAEL > 52 


Required 




Not applicable 


Not required 




Not required 






Table 6 


Safety Limit 












(Clause 5 A) 








Si No. 


Safety Limit 


IG 100 Desigi 


1 Concentration 


Residual Oxygen Concentration ^ 


(1) 


(2) 




(3) 






(4) 




i) 


NOAEL 




43 






12 




ii) 


LOAEL 




52 






10 




'Tercentage by volume. 















Table 7 Human Exposure to IG 100 Agent 

(Clause 5.5 ) 



SI No. 


Exposure 


IG 


100 Agent Concentration ( Percent ) 






'Up to 43 


Between Between 
43 and 52 52 and 62 


More Than 62' 


(1) 


(2) 


(3) 


(4) (5) 


(6) 


i) 


Oxygen concentration ( percent ) 
in sea level equivalent 


12 


Between Between 
12 and 10 10 and 8 


Less than 8 


ii) 


Status of space 


Normally 


Normally Normally 


Normally 






occupied 


occupied occupied 


unoccupied 


iii) 


Exposure time 


Not more 


Not more Not more 


No exposure 






than 5 min 


than 3 min than 30 s 


permitted 



Table 8 Allowable Strength of the Enclosure for IG 100 

( Clause 6.2 ) 



SI No. 


Construction Type 


Typical Structures 


Allowable Load on Enclosure 

kPa 


(1) 


(2) 


(3) 


(4) 


i) 


Light 


Light weight partitions, glazing 


1.25 


ii) 


Normal 


Brick 


4.50 


iii) 


Vault 


Reinforced concrete 


5.00 



7 EXTINGUISHING AGENT SUPPLY 

7.1 Quantity 

a) The amount of the IG 100 in the system 
shall be at least sufficient for the largest 
single hazard protected or group of 
communicating hazards that are to be 
protected simultaneously. 



b) Quantity requirements (reserve ) — Same 
quantity as that of main quantity 
requirements shall be available as reserve. 
However, if the replenishing of agent 
supply takes more than 7 days at the site of 
installation, advice may be sought from the 
authority concerned on further quantity to 
be kept available as reserve. 



IS 15525 : 2004 



c) Uninterrupted protection — Reserve supply 
and main supply should be permanently 
connected to the distribution piping and 
arranged for easy changeover to enable 
uninterrupted protection. 

d) The quantity of the IG 1 00 required shall be 
further adjusted to compensate for any 
special conditions, such as unclosable 
openings, forced ventilation, the free 
volume of air receivers that may discharge 
into the risk, altitude ( substantially above 
or below sea level ) or any other causes for 
the extinguishant loss. 

7.2 Total Flooding Quantity 

a) The amount of IG 1 00 required to achieve the 
design concentration shall be calculated from 
the following equations and this figure shall 
need further adjustment as stated in 7.1(d). 



M= 4.303 



V 



^s^^gio( 



100 



) 



S ^ '^ 100~C 

where 

M = total flooding quantity, kg; 

C = design concentration, percent by 
volume; 

V ^ net volume of the hazard, m"^; 

Kg == volume of the structural/similar 
permanent objects in the enclosure 
that gas can not permeate, in m-^; 

S -/:,+ ^2 (7), where a:, and a:, are 
constants specific to the agent 
used and T is minimum 
temperature inside enclosure; and 

5'p, = specific volume of superheated 
agent at 27''C,m^/kg. 

Specific volume constants for the IG 100 
gas are /C, = 0.799 68 and A:, - 0.002 94. 

IG 100 is a non-liquefied gas at 150 bars. It 
may also be noted that this equation 
provides an allowance for the normal 
leakage from a tight enclosure. 

b) The agent requirement per unit volume of 
protected space can also be calculated by 
using Table 9 for various levels of 
concentration corresponding to the 
temperature within the protected enclosure. 

NOTE — Quantity of the agent shall be the highest 
of the values calculated from the provisions 
contained in 7.2(a) and 7.2(b) above. 

7.3 The actual quantity of IG 100 gas storage 
required and the resultant residual oxygen and carbon 
dioxide concentrations produced shall be 



determined in the following manner, which shall 
further be subject to changes for pressure change due 
to elevation ( see lA ). 

7,3.1 Enclosure Volumes 

The net enclosure volumes are calculated using the 
following equations; 



where 



- V 
Max 



V = maximum net volume of the 

enclosure, m-^; 

V = gross volume of enclosure, m^; 

Kg =" volume of the structural/similar 
permanent objects in the 
enclosure that gas can not 
permeate, m^; 

^Min "^ minimum net volume of enclosure 
considering the maximum 
anticipated volume of the 
occupancy related to the objects 
in the enclosure, in nv"^; and 

V^ = volume of the occupancy related 
objects in the enclosure that gas 
can not permeate, for example, 
furniture fittings, etc, in m^. ( This 
value shall be ignored if the 
volume is less than 25 percent 
of the maximum net volume 



Max 



) 



7.3.2 IG 100 Parameters 

The required IG 1 00 gas quantity, number of cylinders, 
actual injected concentration etc, are calculated using 
the following equations: 



a) IG 100 agent quantity ( Theoretical ) 



where 



■(1) 



A/^,^ = theoreticallG 100 quantity, in m^'; 

^Ma\ ^ niaximum net volume of the 
enclosure, in m^; and 



C, 



appropriate 
concentration. 



injected 



b) IG J 00 Containers 

The number of containers required shall be 
as follows alter rounding off as appropriate: 

N-MJM^ (2) 

where 

jV = number of containers; 



IS 15525 : 2004 



M.. 



theoretical IG 100 quantity, in m^; 8 CONCENTRATION REQUIREMENTS 



and 



M^ =" quantity of IG 100 agent per 
container, inm^. 

Standard containers with standard filling 
pressures should be adopted to facilitate 
logistics. 

c) Actual Quantity ofIG 100 Agent 

The actual quantity of the agent is determined 
as per the equation below: 



(3) 



where 



M^ == actual quantity of IG 100 storage, 
in m^; 

TV = numeral of containers; and 

M^ == quantity of IG 100 agent storage 
container, in m^. 

d) Actual IG 100 injected Concentration 

The actual injected concentration of the agent 
based on the actual quantity of the IG 100 
agent storage is calculated as below: 

C. -M,/K (4) 

AI A Max ^ ^ 

where 

C^^ = actual IG 100 injected 
concentration; 



M^ = actual quantity of IG 100 storage, 
in m^; and 

'^Wx ^ iTiaximum net volume of the 
enclosure, inm^, 

e) Concentration Levels of Oxygen ( ~ ) and 
CO ^ ("^j for the Injected Concentration 

Lastly, it is required to adjust the number of 
IG 100 agent containers, where necessary, 
by compensating for ambient pressure change 
due to location elevation as per 7.4 and 
round off the number as before. The equation 
in such cases will be as follows: 

N^ = Nx atmospheric correction factor 

where 

A^i == adjusted number of containers, and 
A^ = initialnumber of containers. 

7.4 Atmospheric Correction Factors 

It shall be necessary to adjust the actual IG 100 agent 
quantity for altitude effects. Depending upon the 
altitude, atmospheric correction factor shall be 
applied as per the Table 10. The adjusted IG 1 00 agent 
quantity is determined by multiplying the number 
of IG 1 00 containers by the ratio of average ambient 
enclosure pressure to standard sea level pressure. 



8J Fire Extinguishing Concentration 

a) The minimum design concentration of the 
IG 100 agent for Class A surface fire 
hazards shall be the extinguishing 
concentration with a loading of 20 percent 
as a safety factor. 

b) The minimum design concentration of the 
IG 100 agent for Class B hazards shall be 
the extinguishing concentration ( determined 
by Cup Burner test ) with a loading of 
30 percent as a safety factor. 

c) Combustible solids — The minimum 
injected concentration of IG 100 agent for 
surface type class A risks shall not be less 
than 40 percent by volume which yields, on 
a free efflux basis, a residual oxygen 
concentration of 14 percent by volume in the 
enclosure. 

9 APPLICATION RATE AND DISCHARGE 

TIME 

9.1 Rate of Application 

The design application rate shall be based on the 
quantity of IG 1 00 ( M^) [ see 7.3.2(c) j for the desired 
concentration ( see 8.1 or 8.2 as the case may be ) 
and for the time allotted to achieve the design 
concentration ( see 9.2 ). The oxygen and CO^ 
concentrations, however, shall be within the limits as 
specified in 5.3. 

9.2 Duration of IG 100 Discharge 

a) The discharge time period is defined as 
the time required to discharge from the 
nozzles 95 percent of the agent mass at 27^C, 
necessary to achieve the minimum design 
concentration based on a 20 percent safety 
factor for flame extinguishment. 

b) The minimum theoretical injected 
concentration, that is, 34 percent by volume 
shall be achieved within one minute and 
the actual injected concentration [ that is 
the above plus a suitable safety factor, 
adjustment for container : rounding off ] 
shall be achieved within 2 min. 95 percent 
of the minimum design quantity of the agent 
shall be released within 60 s. 

c) Flow calculations performed in accordance 
with 12 or in accordance with the listed 
pre-engineered systems shall be used 
to demonstrate the discharge time 
requirements stated above. 

d) For explosion prevention systems, the 



IS 15525 : 2004 



Table 9 Total Flooding Quantity ( IG 100 ) 

[Clause 7. 2(b)] 



SI No. 


Temperature 

x: 


Specific 
Vapour 
Vo 1 u m e 

mVkg 

S 


Mass Requirements of IG 100 per Unit Volume 
kg/Vj,^^,^jj^^^ Design Concentration ( Percent by 

C 


of Hazard 
Volume ) 




T 


34 


38 


42 


46 


50 


54 


58 


62 


(1) 


(2) 


(3) 


(4) 


(5) 


(6) 


(7) 


(8) 


(9) 


(10) 


(It) 


i) 


-40 


0.682 5 


0.523 


0.601 


0.685 


0.775 


0.872 


0.977 


1.091 


1.217 


ii) 


™35 


0.697 1 


0.512 


0.589 


0.671 


0.759 


0.853 


0.956 


1.068 


1.191 


iii) 


- 30 


0.711 8 


0.501 


0.576 


0.657 


0.743 


0.836 


0.936 


1.046 


1.167 


iv) 


-25 


0.726 4 


0.491 


0.565 


0.644 


0.728 


0.819 


0.917 


1.025 


1.143 


V) 


-20 


0.741 1 


0.481 


0.554 


0.631 


0.714 


0.803 


0.899 


1.005 


1.120 


vi) 


~ 15 


0.755 7 


0.472 


0.543 


0.619 


0.700 


0.787 


0.882 


0.985 


1.009 


vii) 


- 10 


0.770 4 


0.463 


0.533 


0.607 


0.686 


0.772 


0.865 


0.966 


1.078 


viii) 


-05 


0.785 


0.454 


0.523 


0.596 


0.674 


0.758 


0.849 


0.948 


1.058 


ix) 





0.799 7 


0.446 


0.513 


0.585 


0.661 


0.744 


0.833 


0.931 


1.038 


X) 


5 


0.814 3 


0.438 


0.504 


0.574 


0.649 


0.731 


0.818 


0.914 


1.020 


xi) 


10 


0.829 


0.430 


0.495 


0.564 


0.638 


0.718 


0.804 


0.898 


1.002 


xii) 


15 


0.843 6 


0.423 


0.486 


0.554 


0.627 


0.705 


0.790 


0.883 


0.984 


xiii) 


20 


0.858 3 


0.416 


0.478 


0.545 


0.616 


0.693 


0.777 


0.868 


0.968 


xiv) 


25 


0.872 9 


0.409 


0.470 


0.536 


0.606 


0.682 


0.764 


0.853 


0.951 


xv) 


30 


0.887 6 


0.402 


0.462 


0.527 


0.596 


0.670 


0.751 


0.839 


0.936 


xvi) 


35 


0.902 2 


0.395 


0.455 


0.518 


0.586 


0.659 


0.739 


0.825 


0.920 


xvii) 


40 


0.916 9 


0.389 


0.448 


0.510 


0.577 


0.649 


0.727 


0.812 


0.906 


xviii) 


45 


0.931 5 


0.383 


0.440 


0.502 


0.568 


0.639 


0.715 


0.799 


0.892 


xix) 


50 


0.946 2 


0.377 


0.434 


0.494 


0.559 


0.629 


0.704 


0.787 


0.878 


xx) 


55 


0.960 8 


0.371 


0.427 


0.487 


0.550 


0.619 


0.694 


0.775 


0.864 


xxi) 


60 


0.975 5 


0.366 


0.421 


0.479 


0.542 


0.610 


0.683 


0.763 


0.851 


xxii) 


65 


0.990 1 


0.360 


0.414 


0.472 


0.534 


0.601 


0.673 


0.752 


0.839 


xxiii) 


70 


1.004 8 


0.355 


0.408 


0.465 


0.526 


0.592 


0.663 


0.741 


0.827 


xxiv) 


75 


1.019 4 


0.350 


0.402 


0.459 


0.519 


0.584 


0.654 


0.730 


0.815 


xxv) 


80 


1.034 1 


0.345 


0.397 


0.452 


0.511 


0.575 


0.645 


0.720 


0.803 


xxvi) 


85 


1.048 7 


0.340 


0.391 


0.446 


0.504 


0.567 


0.636 


0.710 


0.792 


xxvii) 


90 


1.063 4 


0.335 


0.386 


0.440 


0.497 


0.559 


0.627 


0.700 


0.781 


xxviii) 


95 


1.078 


0.331 


0.381 


0.434 


0.491 


0.552 


0.618 


0.691 


0.770 


xxix) 


100 


1.092 7 


0.326 


0.375 


0.428 


0.484 


0.544 


0.610 


0.681 


0.760 



discharge time for agents shall ensure 
that the minimum inerting design 
concentration is achieved before 
concentration of flammable vapours reach 
the flammable range. 

e) When an extended discharge is desired to 
maintain the design concentration for 
the specified period of time, additional 
quantities of agent can be applied at a 
reduced rate. The initial discharge shall be 
completed within the limits as specified above. 
Performance of the extended discharge shall 
be demonstrated by test. 



f) Where containers are situated remote from 
the protected enclosure, extended transit time 
will be apparent. Authorities concerned shall 
be consulted before locating the containers 
in such cases. 

9.3 Retention Time 

Following the discharge of the agent into the 
enclosure, at least 80 percent of the design 
concentration ( or inerting concentration as the 
case may be ) shall prevail within the enclosure, 
when measured after 10 min of discharge. 



18 15525:2004 



Table 10 Atmospheric Correction Factors 

( Clause 1 A3) 



SI No. 


Equivalent 


Enclosure 


Atmospheric 




Altitude 


Pressure 


Correction 




m 


mm Hg 


Factor 


(1) 


(2) 


(3) 


(4) 


>) 


-920 


840 


1.11 


ii) 


-610 


812 


1.07 


iii) 


-300 


787 


1.04 


iv) 





760 


1.00 


V) 


300 


733 


0.96 


vi) 


610 


705 


0.93 


vii) 


920 


678 


0.89 


viii) 


1 220 


650 


0.86 


ix) 


1 520 


622 


0.82 


X) 


1 830 


596 


0.78 


xi) 


2 130 


570 


0.75 


xii) 


2 440 


550 


0.72 


xiii) 


2 740 


528 


0.69 


xiv) 


3 050 


505 


0.66 



10 STORAGE CONTAINERS 

The IG 100 storage containers shall comply with the 
following in addition to various requirements 
contained in IS 15493. 

a) The containers used in IG 100 systems 
shall be seamless cylinders conforming to 



IS 7285 designed, fabricated, inspected, 
certified and stamped in accordance with 
the requirements of Chief Controller of 
Explosives, Nagpur. 

b) The design pressure shall be suitable for the 
maximum pressure developed at 55°C or at 
the maximum controlled temperature limit. 

c) The storage containers shall have reliable 
means of indicating their pressure. 

d) The storage containers shall have reliable 
means of indicating the variation of container 
pressure with temperature. A pressure/ 
temperature chart ( see Fig. 1 ) attached to 
the container, is acceptable. 

e) The requirements of authorities having 
jurisdiction for containers may take 
precedence over the requirements of this 
standard, if their specifications are more 
stringent. 

11 DISTRIBUTION SYSTEM 

The IG 100 distribution system shall comply with 
the following in addition to various requirements 
contained in IS 15493. 

11.1 Piping Network 

a) The piping shall withstand the maximum 
expected pressure at the maximum storage 
temperature, as follows: 





220 
210 
200 
190 
180 
170 
160 






















> 


^ 






















y 


y 






















/ 


y 






















y 






y 


y 














/ 


/ 






y 


^ 




m 










/ 


/ 




y 


y 








JO 












> 


y 






^ 










ui 


150 

140 

130 

120 

110 

100 


-3 












/ 






y 












CO 




y 


/ 




y 


A 














CL 


y 


/ 




y 


/ 


















/ 


V 


/ 


r^ 1 












: 








^ 


y 
























A 























































-2 





-1 





10 


2C 


3C 


) 4C 


) 5C 


) 6C 


) 7C 


) 8C 


1 90 



TEMPERATURE ,*C 

Fig. 1 Temperature/Pressure Graph FOR IG-100 Pressurized TO 15 MPa and20 MP a at 15°C 

7 



IS 15525 : 2004 



1) 13.5 MPa systems : 20MPaat55°C 

2) 16.2 MPa systems : 25 MPa at55°C 

b) The piping shall withstand the maximum 
developed pressure at 5 5 ""C and shall be in 
accordance with IS 15493. 

c) Carbon steel pipes and fittings shall be 
galvanized inside and outside or otherwise 
suitably protected against corrosion. 
Stainless steel pipes and fittings may be used 
without corrosion protection. 

1K2 Piping Fittings 

a) Pipe fittings shall comply with the 
requirements given in IS 15493. 

b) Fittings shall be selected according to the 
wall thickness or schedule number of the pipe 
to which they are intended to be fitted. 

11.3 Pipe Sizing 

Pipe sizing is a complex issue, particularly when 
too small a bore results in excessive pressure 
losses while two large a bore reduces the flow velocity. 
This may also result in excess pressure drops and 
lower flow rates. The sizes can be checked using an 
approved computer flow calculation programne. 

11.4 Nozzle Placement 

a) The type of nozzles selected, their number 
and placement shall be such that the design 
concentration will be established in all 
parts of the protected enclosure and such 
that the discharge will not unduly splash 
flammable liquids or create dust clouds 
that could extend the fire, create an explosion, 
or otherwise adversely affect the contents 
or the integrity of the enclosure. 

b) Nozzles shall be selected and located to 
protect an area less than its area of coverage. 
The area of coverage to the type of nozzle 
shall be so listed for the purpose. 

c) Maximum nozzle height above floor level 
for a single row of nozzles is 4.5 m. Where 
ceiling height ( of the protected enclosure ) 
exceeds 4.5 m, an additional row of nozzles 
shall be provided for uniform and faster 
distribution of the agent within the 
enclosure. 

d) Minimum nozzle height above the floor 
level of the hazard shall be 0.2 m. 

e) In case of enclosures having no false 
ceiling, nozzles can be located on the ceiling 
anywhere within 0.5 to 5 m from the walls. 
In case of en closure:* having false ceilings, 
deflector shields shafl be used with each 



nozzle and also nozzles shall be so located 
( with an anticipation of dislodgement of 
false ceiling materials or any movable objects 
in the path of discharge ) to prevent any 
damage thereto. 

f) Nozzles shall be provided in all the 
concealed spaces, floor voids, ceiling voids, 
etc, besides the main area within the protected 
enclosure. 

g) Selecting the number of nozzles in a system 
shall take into account, the shape of the 
enclosure ( area and volume ), shape of the 
void ( raised floor, suspended ceiling ). 
Installed equipment in the enclosure/void 
( chimney effect ), allowed pressure at the 
restrictor ( pipe quality ), obstructions, which 
may affect the distribution of the discharged 
agent and architectural considerations. 

h) In hazards having suspended ceiling, 
consideration shall be given for having 
nozzles installed in the ceiling void 
( simultaneous discharge ) in order to 
equalize the pressure during discharge, thus 
reducing the risk of unnecessary damaging 
ceiling tiles, etc. 

j) In hazards having raised floor ( not gas- 
tight ) consideration shall be given for 
having nozzles installed in the floor void 
( simultaneously discharge ) in order to 
equalize the pressure and obtain 
extinguishing concentration below the 
floor. 

k) In hazards having suspended ceiling, 
nozzles for protecting rooms void shall be 
installed in such a way that the jets from the 
nozzles do not damage the ceiling plated 
excessively during discharge, that is, the 
nozzles to be positioned vertically with the 
discharge holes free of the ceiling tiles and/ 
or Escutcheon plates. For light weight ceiling 
tiles, it may be recommended to securely 
anchor tiles for a minimum of 1.5 m from each 
discharge nozzle. 

m) The maximum distance between nozzles 
should not exceed 6 m and the maximum 
distance to wall/partition should not 
exceed 3 m. 

12 HYDRAULICS OF THE SYSTEM 

12 J An approved hydraulic calculation method 
shall be employed to predict pipe sizes, nozzle 
pressure, agent flow rate, discharge per nozzle and 
the discharge time. 

12,2 The various parameters described 



IS 15525 : 2004 



in 7.3.1, 7.3.2, 9.1 and 9.2 shall be considered to 
determine the following minimum limits of accuracy: 

a) The weight of agent predicted by flow 
calculation to discharge from the nozzle 
should agree with the total weight of agent 
actually discharged from each nozzle in the 
system within a range of- 5 percent to + 10 
percent of actual prediction. 

b) The discharge time predicted by the flow 
calculation method should agree with the 
actual discharge time from each nozzle in the 
system within a range of ±5 s. 

c) The accuracy of the calculated nozzle 
pressures versus actual pressures at each 
nozzle should be such that actual nozzle 
pressures in an installation will not fall 
outside the range required for acceptable 
nozzle performance. 

d) The nozzle pressure should not fall below 
the minimum or above the maximum nozzle 
pressure required for the nozzle to 
uniformly distribute the agent throughout 
the volume from which nozzle's discharge is 
to protect. 

13 COMMISSIONING AND ACCEPTANCE 
TESTING 

13.1 Criteria for Acceptance 

The completed IG 100 total flooding system 
shall be commissioned in accordance with 
IS 15493 and the system's performance proved by at 
least one of the following methods: 

a) It is not normally recommended to conduct 
full-scale discharge test of IG 100 total 
flooding systems. Where the authorities 
concerned insist on full-scale discharge test, 
the tests shall be conducted in accordance 
with 14. 

b) Where a full discharge test using IG 100 is 
not insisted by the authorities concerned, 
the following procedure shall apply: 

I) Subject the distribution system to a 
hydrostatic pressure test of 1 .50 times 
the calculated pipework's maximum 



developed storage pressure at 55°C, 
then purge the system to remove 
moisture and prove free passage. 

2) Subject the protected area to an 
enclosure integrity test in accordance 
with IS 15493. 

13.2 Commissioning Certification 

When the system commissioning is completed 
the installation agency shall issue a typical test 
certificate. 

13.3 Where the system fails to comply with 
various provisions as stated above, the fault shall 
be rectified and, if necessary, the system retested. 

14 IG 100 FULL SCALE DISCHARGE TEST 
PROCEDURE 

14.1 This shall be in accordance with IS 15493. 

14.2 Recommissioning 

Restore all systems to a fully operational status. 

14.3 Reporting 

The following shall be reported: 

a) Information identifying the system shall 
include: 

1) Installation, designer and contractor; 

2) Enclosure identifications; 

3) Enclosure temperature prior to 
discharge; 

4) Oxygen and carbon dioxide residual 
concentrations; and 

5) Position of sampling points. 

b) Date and time of test. 

c) Discharge time. 

d) Concentration levels at each sampling 
point at 2 min and 10 min from the 
commencement of discharge. 

e) System deficiencies. 

f) Reference to this test method 
(5ee IS 15493).